This invention relates to structural assemblies for buildings and it is particularly concerned with structural assemblies such as curtain walling in which a number of smaller area panes or panels (referred to hereinafter simply as "panels") are mounted in a frame structure that is not a part of the main load-bearing structure of the building.
In my earlier United Kingdom Pat. No. 1,459,401 (corresponding to U.S. Pat. No. Re. 30,432), there is described such a structural assembly in which a metal framework forms a series of cells for individual infill panels which are supported on the framework and secured by a series of metal T-section auxiliary frame members, a rear centre web of each T-section member slotting into a channel in the front face of an adjoining main frame member while the arms at the front of the T-section carry external sealing gaskets which overlie the front edges of the panels, these gaskets being sealingly clamped against the panel edges by the auxiliary members.
To erect the assembly, the panels must be inserted into their positions while the auxiliary members are only loosely attached to the frameowrk. This must be done before the securing screws between the auxiliary members and the main framework are tightened to clamp the sealing gaskets against the infill and to fix the auxiliary members and the infill securely. That is not an entirely satisfactory method because the infill panels have to be handled with particular care and skill if the only partially secured auxiliary members are not to be deflected or even distorted before they can be firmly fixed in position. This difficulty grows as the panels increase in thickness and weight and is therefore particularly significant if double-glazed panels are utilised.
Moreover, although the transfer of heat through a curtain wall having this known construction is limited by the arrangement of the sealing gaskets to cover the outer faces of the auxiliary members, so that the metal members are not directly exposed to external temperature extremes, there is nevertheless close contact over a large area between the web of the T-section and its mating channel in the main framework. This provides a substantial heat-conductive path bridging the infill panels even though the front faces of the auxiliary members have the sealing gaskets shielding them from the exterior.